Fixed some heading levels in README.
Fixed some heading levels in README.

dsager/prax,ychaim/prax,ychaim/prax,ysbaddaden/prax,Kriechi/prax,dsager/prax,Kriechi/prax,ysbaddaden/prax,Kriechi/prax,ychaim/prax,dsager/prax,ysbaddaden/prax,Kriechi/prax,ysbaddaden/prax,ychaim/prax,dsager/prax